Dispersion of gums



Patented May 22, 1945 D STATES nrsrsnsron or spars Ben F. Buchanan,Leonie, N .J asslgnor to American Maize-Products Company, a corporationoi Maine No Drawing. Application May 26, 1942, Serial No. 443,845

Claims.

This invention relates to a composition for promoting dispersion of agum in water and particularly to the dispersion of a true gum in suchmanner as to prevent the lumping together of the gum and to effect thedispersion quickly and completely.

In dispersing a true gum in water, it is customary to mix the gum individed form with water and allow a relativelylong period of time forthe gum to soak in the water. During this soaking period, the gumhydrates and forms a gelatinous film around particles that may be nearlyor quite dry in the center. These particles with the exterior gelatinouscoatings form lumps or balls, so that a relatively long time orextremely vigorous agitation is required to disperse the gum completelyin the water.

To minimize this dimculty, premixing of the gum in dry form withsucrose, dextrose, or other sugar in large volume has frequently beenresorted to so as to space apart the particles of gum and thus reducethe tendency to lumping when the gum is stirred into water.

The present invention provides a method and composition for overcomingthe dificulties in the dispersion of the gums without th need ofpremixing with a large bulk of sugar or like separating agent.

Briefly stated, the invention comprises the.

composition resulting from mixing a true gum with a water solublelactate salt, preferably in proportion that is minor as compared to theamount of the gum. In the preferred embodiment, the invention comprisesthe admixture also of a very small proportion of water in addition tothat normally present in most of the gums, the proportion of theadditional water used being Just adequate to make the particles of gumnondusty and slightly moist Without converting the surface portions ofthe particles to a sticky condition.

Compositions made as described and then stirred into cold or tepid wateror other aqueous dispersing medium disperse quickly without theintermediate formation of objectionable lumps or -balls.

As the gum used there is selected what is called herein a true gum asdistinguished, for example, from rubber, chicle, and other waterinsoluble materials that are sometimes referred to as gums.

The term true gum is used herein to mean a natural gum that is solublein water, dries to to being reduced to powdered, granulated, or flakedform, as by milling or spray or drmn drying. These gums normally containaround about 5 to 12% of water, but even in such condition are fiowable,that is, may be poured from a sack or container since they are not sosticky as to form large coherent masses of material.

Among such true gums that may be used to advantage in the presentinventionare tragacanth, karaya, locust bean gum, and water solublealginic acid compounds including the acid itself and its alkali metal(sodium, potassium, and ammonium) salts. Other gums meeting the generalrequirements stated may be substituted for those specifically named.

The lactate to be used must be in the form of a water soluble salt.Thus, there may be used the alkali metal lactates including sodium,potassium, and ammonium lactates, calcium lactate, and lactates of theammonium derivatives such as the amines, particularly triethanolaminelactate. Magnesium and zinc lactates' are appreciably soluble in waterand are operative for the present purpose although objectionable becauseof taste or physiological properties when the product is to be Used inthe food industries. The triethanolamine lactate also is not recommendedin making food materials.

The proportion of lactate may vary considerably but should be minor, forexample, 0.1 to 5 parts for parts of the selected gum, the pro portionsbeing by weight and on the dry basis. Somewhat more than 5 parts of thelactate may be used, although such larger proportion is unnecessary.Preferably I use about 0.3 to 2.5 parts of the lactate to 100 parts ofthe gum.

The lactate may be mixed with the gum in solid divided condition, say aspowder, granules, or flakes. Or the lactate may be" incorporated intothe solution of the gum before the latter is reduced to solid form, incase the gum during its normal preparation for commercial distributionis obtained in the form of a solution previous to solidification, as isthe case in the manufacture of the alginates, for example. In any case,the lactate is mixedwith the gum before the gum is incorporated into thelarge amount of water in which the gum is to be ultimately dispersed.

For best results, but not necessarily for all purposes, the gum andlactate mixture is made slightly moist in advance of introduction intothe a firm product upon evaporation of most of the wa'ter normallyassociated with the gum in its natural state, and when so dried issusceptible whole mass of water for effecting final dispersion.

Thus, there is admixed a limited amount of water,

suitably about 0.2 to 4 or 5%. of water on the weight of the gum. Theuse of this water in advery soluble and has alkali metal lactate ditionto that normally present in the gum used increases the rate ofdispersion of the gum considerably over that obtained by theincorporation of lactate alone.

The proportion of water varies somewhat with the particular lactateselected. A lactate that is a tendency to absorb and retain moisturerequires somewhat less water than one that does not have theseproperties. Thus, the proportion of water used within the above rangemay be somewhat smaller with an than with calcium lactate. With thelatter, a minimum of about 0.5% of moisture on the weight of the gum ispreferred.

The small amount of moisture added in this manner serves to distribute asubstantial part of the lactate as a film over the individual particlesof the gum and thus-promote intimacy of association with or evensolution of the lactate in the surface portions of the said particlesbefore the whole is introduced into the water for the ultimatedispersion.

The invention will be further illustrated by the following specificexamples of the practice of it. Exnsrnn 1 Formula Parts Sodium alginate98 Sodium lactate solution (50% water); 2 Procedure These materials areintimately mixed, so that the alginate is no longer in the originaldusty form. The mixed composition is then dispersed in an excess ofwater, say, from 20 to 80 parts of water to 1 part of the composition.

Such dispersion is accomplished readily by adding the water in cold ortepid condition directly, gradually, and with constant stirring, to thegum and lactate composition. In this manner, hydration of the gum isaccomplished within a relatively short time, ordinarily about '2 to 5minutes, whereas without the lactate vigorous agitation would berequired for from 20 minutes to 1 hour to cause hydration of thealginate sufficiently for use.

EXAMPLE 2 Formula Parts Ammonium alginate 96 Calcium lactate (mono orpenta hydrate) 4 Procedure These two materials 'in finelydivided-condition are thoroughly mixed in thedr condition and dispersionaccomplished by adding gradually the desired amount of cold or tepidwater directly to th dry mixture with constant stirring during theaddition of the water.

Hydration of the gum when the mixture is stirred with water proceeds inabout thesame manner as in Example 1, although not so rapidly, since thegum has not been prewetted with a small proportion of water.

Exmrnr: 3

The procedures of Examples 1 and 2 is followed except that another ofthe alginic acid compounds, gum tragacanth, karaya, locust bean tiallyof a true gum gum or a mixture of them is substituted part for part forall or a part of the alginates used in the examples. In each case, agreat improvement in the rate .0! dispersion in cold water is obtaineddue to the use of the lactate.

In place of water as the dispersion media there may be used otheraqueous media, as for example milk or cream and sweetened, flavored, orcolored water.

The compositions made as described are useful in the manufacture of icecream, ices, and frozen desserts in genera, the composition beingsubstituted for the usual gum component, ordinarily the stabilizer, ofsuch products on the basis of parts of the gum in my composition for anequal weight of the gum as used previously. i

The composition may also be used in the confectionery and bakeryindustry in place of the gums conventionally used alone for stabilizingwater dispersions as. for example, for the prevention of weeping orslowness of setting of marshmallows.

The lactates seem to be unique among salts in their action in increasinggreatly the dispersion rate of the true gums. Tests with closely relatedproducts including salts of such other hydroxy acids as tartaric andcitric acids have failed to develop a satisfactory substitute for thelactate. The lactates make the rate of dispersionof the gum so largethat the gum dissolves (disperses) before it can form into difficultlydispersible balls.

' It will be understood also that it is intended to cover all changesand modifications of the example of the invention herein chosen for thepurpose of illustration which do not constitute departures from thespirit and scope of the invention.

What I claim is:

1. A composition of matter consisting essentially of a true gum in solidcomminuted condition and as a dispersing material a water solublelactate salt intimately mixed with the particles of the gum, theproportion of the lactate salt being 0.1 to 5 parts by weight for 100parts of the gum. v

2. A composition of matter consisting essenin solid comminuted conditionand as adispersing material a water soluble lactate salt intimatelymixed with the particles of the gum in the proportion of 0.1 to 5 partsof 3. A composition as described in claim 1, the

gum being a water-soluble alginate.

4. A composition as described in claim 1, the gum being gum tragacanth.

5. A composition of matter as described in claim 1, the said lactatesalt being sodium lactate and the proportion of it being 0.3 to 2.5parts by weight for 100 parts of the gum.

BEN F. BUCHANAN.

